<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <script src="./lib/vue-2.4.0.js"></script>
</head>

<body>
    <div id="app">
        <input type="button" value="浪起来" @click="lang">
        <input type="button" value="低调" @click="stop">
        <h4>{{msg}}</h4>
    </div>
</body>

<script>
    var vm = new Vue({
        el: '#app',
        data: {
            msg: '猥琐发育，别浪~~！',
            intervalId: null
        },
        methods: {
            lang() {
                if (this.intervalId != null) return;
                // console.log(this.msg);
                this.intervalId = setInterval(() => {
                    var start = this.msg.substring(0, 1)
                    var end = this.msg.substring(1);
                    this.msg = end + start;
                }, 400);
            },
            stop() {
                clearInterval(this.intervalId);
                this.intervalId = null;
            }
        }
    });
</script>

</html>